enhance(#2778): make the size-ratchet failure name its own remedy (#2780)

* fix(#2778): exempt intentionally-absent paths from the glossary gate

check-glossary-refs asserts that every backticked tests/ token in
CONTEXT.md resolves on disk. tests/emitted-drift-ack.json (ADR-2719
section 3) is absent on a healthy next BY DESIGN — it appears only
inside a PR that needs it, which is what makes touching it the alarm.

It passed before only by accident of backtick pairing: CONTEXT.md's
RULESET entries are themselves backtick-wrapped and contain backticks,
so the token happened to fall outside a code span. Any edit that
shifted the parity exposed it. A gate that passes by luck is not
passing.

The exemption is exact, not a prefix hole: a sibling missing tests/
path still fails, and a test locks that.

* feat(#2778): make the size-ratchet failure name its own remedy

The growth branch stated a requirement and withheld the means of
satisfying it: no ack file named, no schema, no key format, and no
do-not-regenerate line — so the likeliest guess was to hunt for a
baseline that #2724 deleted. Observed live on #2543.

All remediation now comes from one frozen REMEDIATION export whose
example document is rendered from ACK_VERSION, so the taught schema
cannot drift from the schema parseAck accepts. A round-trip test feeds
the printed document back through parseAck.

The report is now built as a typed IR (buildReport) that formatReport
renders, so tests assert on structure rather than prose, per
CONTRIBUTING.md's raw-text-matching rule.

Two defects found and fixed inline while building:
- diffEmitted's validation early-return omitted newFileCapExceeded
  while formatReport reads its length, so the branch that reports a
  failed git diff threw a TypeError instead of naming the problem.
- Printing one complete ack document per failing branch made each read
  as the whole file, so pasting the second over the first silently lost
  an acknowledgment. One document now covers the whole report.

Closes #2778

* chore(#2778): backfill changeset pr number to 2780

.changeset/zesty-orcas-dart.md

@@ -0,0 +1,5 @@
+---
+type: Changed
+pr: 2780
+---
+**The emitted-attribution size ratchet now tells you how to clear it** — a PR that only grew a workflow or agent file used to fail with a byte delta and the word "acknowledgment", without naming `tests/emitted-drift-ack.json`, saying it does not exist yet, giving its schema, or stating that the key is the bare filename. All three failing branches now print a minimal valid document and repeat that nothing is regenerated. (#2778)